如何从不同结构的值初始化结构

时间:2019-01-25 13:22:07

标签: swift codable swift-structs

我有一个要存储的用户个人资料,结构像这样

struct Profile: Codable {

    let company: String?
    let country: String?
    let createdDate: String?
    let dateOfBirth: String?
    let department: String?
    let email: String?
    let employeeKey: String?
    let firstName: String?
    let gender: String?
    let id: String?
    let jobTitle: String?
    let lastName: String?
    let location: String?
    let mobileDeviceToken: String?
    let pictureUri: String?
    let roles: [String]?
    let status: String?
    let updatedDate: String?
    let userId: String?
    let webDeviceToken: String?
    let webMobileDeviceToken: String?

    enum CodingKeys: String, CodingKey {
        case company = "company"
        case country = "country"
        case createdDate = "createdDate"
        case dateOfBirth = "dateOfBirth"
        case department = "department"
        case email = "email"
        case employeeKey = "employeeKey"
        case firstName = "firstName"
        case gender = "gender"
        case id = "id"
        case jobTitle = "jobTitle"
        case lastName = "lastName"
        case location = "location"
        case mobileDeviceToken = "mobileDeviceToken"
        case pictureUri = "pictureUri"
        case roles = "roles"
        case status = "status"
        case updatedDate = "updatedDate"
        case userId = "userId"
        case webDeviceToken = "webDeviceToken"
        case webMobileDeviceToken = "webMobileDeviceToken"
    }
}

我还有另一个看起来像的结构

struct ArticleAuthor {
    let name: String
    let department: String
    let email: String
}

获取用户个人资料时,我希望能够使用从我的个人资料服务返回的个人资料对象创建ArticleAuthor结构。

我希望做这样的事情,但是由于from值应该是数据,所以它不起作用。

        self?.profileService.fetchForUserByUserId(userId: authorId) { [weak self] profile, error in
            guard error == nil else { return }

            let author = try? JSONDecoder().decode(ArticleAuthor.self, from: profile)

                print(author) // should be a populated author property

        }

我希望避免使用let author = ArticleAuthor(name: profile?.firstName, department: profile?.department, email: profile?.email)之类的东西,因为该对象可能会随着时间增长。

1 个答案:

答案 0 :(得分:2)

示例代码中的配置文件对象已被“解码”,因此您无需再次对其进行解码。

为避免使用默认的init,只需添加一个自定义的初始化程序,以便可以传入Profile结构并设置值。通常,这是最好的解决方法,因为当您添加新属性时,它可以防止在整个代码库中进行大量更改

struct ArticleAuthor {
    let name: String?
    let department: String?
    let email: String?

    init(profile: Profile) {
        self.name = profile.firstName
        self.department = profile.department
        self.email = profile.email
    }
}

self?.profileService.fetchForUserByUserId(userId: authorId) { [weak self] profile, error in
    guard error == nil else { return }

    let author = Author(profile: profile)
    print(author) // should be a populated author property
}